Distance finder systems of several varieties that are directed to use for a number of purposes have been developed. Some of these prior art systems incorporate a laser beam that is utilized to determine and measure distances. Such prior art systems incorporate a narrow laser beam that is directed to a discrete point and the system is operable to determine a measurement to the location where the discrete point of the laser beam meets a surface, such as a wall.
Prior art distance finder systems further integrate a lens when such systems are utilized to determine distances prior to the capture of either still or motion images by a camera. For example, a distance finder may be positioned parallel to a camera lens that is a long lens. The field of view of a long lens is limited and such lenses are routinely utilized to capture close-up images in which a single item, person or other feature fills, or nearly fills the frame of the image. In such prior art systems the laser is aimed at the center of the frame in tandem and virtually parallel to the camera lens. The narrow laser beam hits a discrete point directly in front of the camera lens and a measurement reading is determined based upon that discrete point.
Such prior art systems incorporate a means whereby the measurement is made available to a user of the system, such as a screen incorporated in the apparatus that houses the laser beam and that is attachable to the camera. The screen is operable to show the measurement in a form that is readable by a user.
An example of a prior art system is the Cfinder™ system that is an optical distance measurement tool that incorporates an invisible class 1 laser for distance measurements and a visible class 2 laser as a pointer. The system can be utilized to focus on a small point on a target object during filming by way of the invisible laser, causing the measurement stream to be invisible. In this manner the Cfinder system can be utilized to measure the distance to a particular object. The visible laser can be utilized to show as a visible red dot the point on the target object where the laser beam is focused for the purpose of undertaking the distance measurement. The Cfinder system is part of the Cmotion™ system that further incorporates Cfocus™ that is focus assistance software. Cfocus provides a user with information by way of a display that is a measurement of the distance to a subject. The Cfinder component is attachable to a camera or may be mounted on a tripod. The Cfinder is solely operable to measure distance to the point where the laser beam contacts the target object.
The Cine Tape Measure™ is another example of a prior art distance measurement system utilized with a camera. This is an ultrasonic system that continuously measures the distance between a subject and a point on the film-plane through the use of ultrasonic waves. The measurements can be utilized to focus the camera lens in relation to the discrete point on the film-plane during the capture of an image. The invention is only operable to determine measurements to a discrete point on a target object.
Cinetape Extension Tubes™ may further be attached to the sensor of the Cine Tape Measure to create a tighter measuring area. The Cinetape Extension Tubes narrow the measurement field by about twenty percent. The ultrasonic waves are directed by the tubes towards the sensors which results in narrowing the measurement field. Notably, the tubes do not modify the characteristics of the ultrasonic waves, these remain cone-shaped. The tubes modify the cone angle by about twenty percent.
Yet another example of a prior art system is the Panatape LongRange™, a product of Panavision™. The Panatape LongRange is a low level laser finder that shows to a user the distance from the film plane to an object. The Panatape LongRange is mountable on a camera. The laser is directed to a target point in the distance, and the distance from the point to the film plane is measured by the system. The measurement is displayed to a user on a display that is incorporated in the system. The Panatape LongRange can be utilized with a smart zoom lens or other types of lenses. The Panatape LongRange solely measures distance to a discrete point on an object.
One prior art system is disclosed in U.S. Pat. No. 5,092,670, granted on Mar. 3, 1992 and invented by Howard J. Preston, that is an automatic focusing system for use with a motion picture camera. This system includes a variable focus lens attached to either motion picture camera or a video camera, and an adjusting mechanism of a lens focus barrel which adjusts the variable focus lens so that an image of a photographic subject is in focus on a focal plane. A pan/tilt head is mounted on a tripod. The automatic focusing system includes a plate, a motorized turntable, a housing and a rangefinder. The plate is mounted on the pan/tilt head. The camera is mounted on the plate. The motorized turntable is also mounted on the plate. The motorized turntable is servo controlled. The motorized turntable is disposed to a fixed and known first distance from the camera and is made to rotate along an axis parallel to the pan-axis of the pan/tilt head. The housing is mounted on the motorized turntable. The rangefinder is disposed in and mechanically coupled to the housing. The rangefinder determines a second distance to the photographic subject from the housing. This invention requires a triangulation set-up of equipment in order to measure distance.
U.S. Pat. No. 6,724,429, granted on Apr. 20, 2004 and invented by Morris Shore, Wynn Bowers, Vince H. Catlin, Felipe Navarro, and Christopher J. Verplaetse, further discloses a system for sensing and displaying lens data for a cinematography zoom lens and camera in real time. This invention captures as lens data a distance measurement by way of a rangefinder that may be mounted adjacent to the lens and usually above the lens, and that determines the actual distance from the lens to an object being photographed that is positioned in front of the lens. However, this invention does not incorporate a laser beam in the distance measurement of the system, and is operable solely to measure the distance between a lens and a point on a target object.